Dot indexing is not supported for variables of this type when trying to write value into static text box

function text7_CreateFcn(hObject, eventdata, handles)
value=1;
set(handles.text7, 'String', num2str(value))

I am trying to add a value that will be determined by a slider in my GUI into the text of a static text box, but recieve the error message 'Dot indexing is not supported for variables of this type'

[Samuel Leeney]

Any help on this would be much aprpeciated as it is the final part I am stuck on for a project, and have next to no help as teaching is 100% online. Thanks!

[Ameer Hamza]

Is this created in App designer?

[Samuel Leeney]

No, it's created using guide, the older software. I'm not a fan of app designer.

Answer 1

[Image Analyst]

Do not put anything into the CreateFcn() functions of controls. If you want something to be initialized with a value, then put that value into the String property of the control in GUIDE, not in the CreateFcn.

Now, to get the value of a slider and put it in the text box as you move the slider, you'd put it into the callback function of the slider, not the callback of the text box.

function slider1_CallbackFcn(hObject, eventdata, handles)
value = handles.slider1.Value;
textLabel = sprintf('Slider = %.3f', value);
% Update text box
handles.text7.String = textLabel;

Answer 2

[Fangjun Jiang]

set(hObject, 'String', num2str(value))

see this comment ?

% hObject    handle to edit1 (see GCBO)

% handles    empty - handles not created until after all CreateFcns called

[Samuel Leeney]

Thanks for your reply, I'm not really sure what you mean?

Could you clarify please.

[Rik]

The handles struct has not been created yet, so you need to use the handle to the object itself.

Also, do yourself a huge favor and don't use GUIDE for anything you spend more than 10 minutes making. Link

[Samuel Leeney]

Like this? set(handles, 'String', num2str(value))

Thanks, I actually tried migrating this across to app designer but it didn't go across properly. I will probably use app designer in the future. We have next to no support from the professor's this year due to the pandemic so have been making quite a few basic mistakes with stuff like this!

[Rik]

No, set(hObject,'String',num2str(value)).

Using a programmatic GUI (and not AppDesigner) offers a wide variety of benefits. I would encourage you to check out the thread I linked in my previous comment.

Answer 3

[Walter Roberson]

function text7_CreateFcn(hObject, eventdata, handles)
value = 1;
set(hObject, 'String', num2str(value))